Sunday, June 03, 2007

About That Consensus

"Only an insignificant fraction of scientists deny the global warming crisis. The time for debate is over. The science is settled."

So said Al Gore . . . in 1992. Amazingly, he made his claims despite much evidence of their falsity. A Gallup poll at the time reported that 53% of scientists actively involved in global climate research did not believe global warming had occurred; 30% weren't sure; and only 17% believed global warming had begun. Even a Greenpeace poll showed 47% of climatologists didn't think a runaway greenhouse effect was imminent; only 36% thought it possible and a mere 13% thought it probable.

Today, Al Gore is making the same claims of a scientific consensus, as do the United Nation's Intergovernmental Panel on Climate Change and hundreds of government agencies and environmental groups around the world. But the claims of a scientific consensus remain unsubstantiated. They have only become louder and more frequent. . .

[T]he list of distinguished scientists who question the IPCC grows daily, as does the number of emails I receive, many from scientists who express gratitude for my series.

Somewhere along the way, I stopped believing that a scientific consensus exists on climate change. Certainly there is no consensus at the very top echelons of scientists -- the ranks from which I have been drawing my subjects -- and certainly there is no consensus among astrophysicists and other solar scientists, several of whom I have profiled. If anything, the majority view among these subsets of the scientific community may run in the opposite direction. Not only do most of my interviewees either discount or disparage the conventional wisdom as represented by the IPCC, many say their peers generally consider it to have little or no credibility. In one case, a top scientist told me that, to his knowledge, no respected scientist in his field accepts the IPCC position.

The supposedly "settled" science on global warming is like a Soviet election--and, amazingly, Brezhnev's still getting 98 percent.

MORE:

The IPCC website claims a "mandate" "to assess on a comprehensive, objective, open and transparent basis the scientific, technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation." I agree with Ken McCracken of WILLisms that this assumes the conclusion.

2 comments:

There are a couple of ways you can approach the global warming debate. You could have a scientist roll call to see which side looks the most impressive. On the one hand, you have a scattering of scientists as presented in the National Post series. On the other side, you have the IPCC saying man causes global warming. Or if the IPCC is not your cup of tea, there's always the Academies of Science from 19 countries endorsing the IPCC's position. Or NASA's Goddard Institute of Space Studies, the National Oceanic and Atmospheric Administration, Environmental Protection Agency, American Geophysical Union, American Institute of Physics, National Center for Atmospheric Research and American Meteorological Society.

However, roll calls don't really interest me. It's more relevant to examine peer reviewed journals - scientists can have their theories but they need to back it up with empirical evidence and research that survives the peer review process. A survey of all peer reviewed abstracts on the subject "global climate change" published between 1993 and 2003 show that not a single paper rejected the consensus position that global warming is man caused. 75% of the papers agreed with the consensus position while 25% made no comment either way (eg - focused on methods or paleoclimate analysis).

Personally, I like to examine each argument on a case by case basis. Here's the arguments used in the National Post series that try to explain global warming without CO2:

Part 1: "The hockey stick was debunked due to statistical errors." Since the initial hockey stick study by Mann and its subsequent "debunking", there's been around a dozen proxy studies, analysing a variety of different sources including corals, stalagmites, tree rings, boreholes, ice cores, etc. The results all confirm the same general conclusion: the 20th century is the warmest of the entire record, and that warming was most dramatic after 1920. This is even confirmed by Stephen McIntyre, one of the original hockey stick debunkers.

Part 6: "Less cosmic rays => less clouds => global warming." The big flaw in the cosmic ray theory is cosmic radiation has shown no trend over the last 50 years. So even if cosmic rays are linked to cloud formation, all they'll find is the cloud formation 50 years ago is the same as it is now and has little to no impact on global warming today.

Part 9: Mars is warming. The whole theory that a brightening sun is causing global warming falls apart when you consider solar output hasn't risen over the last few decades of global warming according to direct satellite measurements that found solar output has shown no rising trend since 1978, sunspot numbers which have leveled out since 1950, the Max Planck Institute reconstruction that shows irradience has been steady since 1940 and solar radio flux or flare activity which shows no rising trend over the past 30 years. So what's causing warming on Mars? The planet has had massive darkening storms over the last 30 years that reduce the planet's albedo (reflectivity) which warms the planet.

Part 10 rehashes Part 6 and 9, blaming the sun and cosmic rays. Again, solar activity and cosmic radiation have shown no long term trend over the same period global warming has been greatest. If there is a "smoking gun" in global warming, solar variations sure ain't it.